Multiple record, single marker recording system



Oct. 24, 1950 a. w. BARNES, JR 2,527,207

IIULTIPLE RECORD, SINGLE mama nncoaomc SYSTEM 6 Sheets-Sheet 1 Filed April 12, 1944 FIG.

INVENTOR. GEORGE W BARNES JR.

ATT

Oct. 24, 1950 w, BARNES, JR 2,527,207

ULTIPIE RECORD, SINGLE MARKER RECORDING SYSTEM Filed April 12, 1944 6 Sheets-Sheet 2 FIG. 2

L11111.!11111M1II1IH y l INFIIII F \i J mh 1 lllmm'li Ihlhl 1 1 1 1 1" I 1 11 I V i I l 8* 2f 1:!

l i I in 1111--"*"""" 1 1 1 111111 lf |11If f1111111 H l Q I 1 1 I a 1 1 1 I 8 8 111111 111111 1| 1|||||I|| WW I. A Q Q a O 0 1L. 1 n l' 6 FIG l2 2 2 T w 2 25! 255 GEORGE w. BARNES JR.

: ATTOREEY.

Oct. 24, 1950 e. w. BARNES, JR 2,527,207

MULTIPLE RECORD, SINGLE MARKER RECORDING SYSTEM 6 SheetsSheet 3 Filed April 12, 1944 FIG. 3

[NI 'EN I'OR. GEORGE W. BARNES JR ATTORNEY Oct. 24, 1950 a. w. BARNES, JR 2,527,207

MULTIPLE RECORD, SINGLE MARKER RECORDING SYSTEM Filed April 12, 1944 6 Sheets-Sheet 4 FIG. 4 ass 62 as 97 II l2! w 7 H9 n4 j 6 INVENTOR. GEORGE w. BARNES JR.

L 1 I09 BY 1. 1 1 m n3 -u? ATTO NEY.

Oct. 24, 1950 e. w. BARNES. JR

MULTIPLE RECORD, SINGLE MARKER RECORDING SYSTEM Filed April 12, 1944 6 Sheets-Sheet 5 ATTORNEY.

1950 e. w. BARNES. JR 2,527,207

MULTIPLE RECORD, SINGLE MARKER RECORDING SYSTEM 6 Sheets-Sheet 6 Filed April 12, 1944 INVENTOR. GEORGE W. BARNES JR.

ATT NEY.

Patented Oct. 24, 1950 UNITED STATES PATENT OFFICE MULTIPLE RECORD, SINGLE MARKER RECORDING SYSTEM Application April 12, 1944, Serial N0. 530,611

15 Claims.

The present invention relates to recording instruments, and more particularly recording instruments that are used to make simultaneously records of the values of two conditions on rectangular coordinates.

In most recording instruments the value oi. a single condition is recorded against time by moving a marking element in one direction and moving the chart upon which the record is made at right angles thereto and at a constant speed. There are times, however, where it is more desirable to record the value of one condition with respect to the value of a second. In such a case a more complicated instrument is necessary since means must be provided for moving the marking element in two directions.

It is an object of the invention to provide an instrument in which the values of a plurality of variable conditions may be recorded simultaneously with a single recording element. It is a further object of the invention to provide an instrument in which a recording element is moved in one direction in response to variations in the value of one condition and in which the recording element is moved in a direction at right angles to the first direction in response to variations in the value 01' a second condition.

It is a further object of the invention to provide an instrument in which the value of one condition may be successively plotted against the values of a plurality of other conditions. In order that the various records made may be distinguished from each other a means is provided to give a characteristic marking to each of the records.

The instrument of the present invention is provided with a pair of motors each one of which, through suitable mechanism, serves to move the recording element across the chart in one direction. Each of these motors is controlled in its rotation by means 01' an amplifier that is responsive to the variations in a minute electric voltage. This voltage is directly responsive to variations in the condition being measured, such, for example, as the voltage produced by a thermocouple if temperature is being measured, or from a tachometer generator it speed is being measured. The chart upon which the record is made is drawn with rectilinear coordinates and is manually moved to bring a new surface under the recording element each time a record is to be made.

It will be obvious to those skilled in the art that any two variables may be plotted against each other such as temperature against pressure, speed aga nst distance, specific gravity against iiow, or other variables. This invention is more particu- 2 larly interested with the recording mechanism, rather than the variables whose values are recorded.

The various features of novelty which characterize this invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects obtained with its use, reference should be made to the accompanying drawings and descriptive matter in which is illustrated and described a preferred embodiment of the invention.

In the drawings:

Figure 1 shows a front view of the instrument with the casing door open,

Figure 2 is a view of the instrument casing with the chassis swung out of position,

Figure 3 is a back view 0! the mechanism supported on the chassis,

Figure 4 is a top view of the chassis,

Figure 5 is a bottom view of the chassis,

Figure 6 is a view of the paper feeding mils taken on line 88 of Figure 4.

Figure 'i is a view taken on line 1-1 of Figure 6.

Figure 8 is a sectional view oi the chart supporting roll,

Figure 9 is a view taken on line 9! shown in Figures 1, 4 and 5,

Figure 10 is an enlarged front view of the pen supporting carriage,

Figure 11 is a top view of the pen supporting carriage taken on line I I --H shown in Figures 1 and 9,

Figure 12 is a view of the actuating mechanism for the pen lifter,

Figure 13 is a sectional view taken on line lt-Il of Figure 5,

Figure 14 is a view in section 01' a portion of the vertical driving mechanism,

Figure 15 is a view of the standardizing mechanism,

Figure 16 is a wiring diagram for the measuring circuits, and

Figure 17 is a view showing the chart record identifying system.

Referring first to Figures 1 and 2, there is shown an instrument casing I which is rectangular in shape and which has a door I mounted thereon by hinges I. The door is shown in its open position so that the parts within the casing may be seen. The chart supporting mechanism and the recording mechanism are both mounted on a chassis 4 that is swingably mounted in the in.

strument casing. To this end the chassis is provided with hinge members that cooperate with hinge members 6 on the casing. Hinge pins 1 extend through the members 5 and 6. so that the chassis is pivotally mounted. The chassis is held in position in the casing 2 by means of a lock 8 that is actuated by a knob 9.

When the lock is released and the chassis is swung out of the case, the interior of the casing will be exposed as shown in Figure 2. In this figure there is shown a pair of amplifiers II and I2 that are mounted upon the back of the casing. Mounted upon the side wall of the casing in line with each other are dry cells I3, one of which is used with each of the amplifiers. A series of terminal blocks I4 are also attached to the back of the casing so that the various electric connections may easily be made. In the drawings the wires which extend between the various parts of the instrument are omitted for the sake of clearness; the connections, however, are similar to those which are shown in the wiring diagram of Figure 16. The case is deep enough and the parts are so arranged on it and on the chassis that they do'not conflict with each other when the chassis is swung into its position in the case.

Each of the amplifying units forms part of a complete potentiometer type circuit of the kind disclosed and claimed in the application of Walter 1?. Wills. Serial Number 421,173, filed on December 1, 1941. These circuits are, however. connected in a novel manner so that the amplifying unit for one circuit may be used to standardize both circuits. The tyoe of primary measuring element used has not been shown since it is immaterial, and may be responsive to any variable as long as a voltage varying in accordance with the value of the variable is produced. For example, for purposes of this description only, it may be assumed that a graph is being made of temperature plotted against pressure, with temperature as the ordinate and pressure as the abscissa.

The potentiometer circuit or network on the left in Figure 16 is normally connected with the amplifier II. This circuit is provided with a slidewire I5 across which is impressed a potential by one of the batteries I3. As the battery voltage decreases with use the potential may be adjusted to a constant value by means of a variable resistance IIi. An unknown voltage proportional to the variable is impressed across the slidewire in opposition to the known voltage. This unknown voltage is applied to terminals I1 and I8. From terminal I] connection is made direct to a collector bar I9 and a contact M to the slidewire I5. From terminal I8 connection is made through stationary contact 22, movable contact 23. of a switch 20, and wire 24 to a center tap on the primary of a transformer forming part of a converter Ila that is built into amplifler II. Connection is made from the converter, by wire 25 to a point 26 in the potentiometer network. When the potentiometer network is unbalanced due to a change in the input voltage, this unbalance is detected by the converter and amplified in a manner set forth in the above mentioned Wills application to energize a motor 21 for rotation in a direction dependent upon the network unbalance. As the motor 21 rotates it moves the contact 2| along the slidewire I5 and collector bar III in a direction and amount to rebalance the network and simultaneously adjusts a recording element.

The potentiometer network on the right of Figure 16 is similar to that on the left in that it is provided with a slidewire 28 across which a known voltage is impressed by a battery I80, the voltage being kept constant as the battery diminishes by a rheostat 29. The unknown voltage is applied to terminals 3i and 32, the former of which is connected directly with a collector bar 33 and movable contact 34. The terminal 32 is connected through stationary contact 35 and movable contact 36, of a switch 31, stationary contact 38 and movable contact 39 of the switch 20, wire 4I, Junction 02 and wire 43 to the center tap of the primary winding of a transformer forming part of a converter I2a of the amplifier I2. From the converter connection is made through wire 44 to a movable contact 45 and a stationary contact 48 of the switch 20 to a point 41 of the potentiometer network. As the network is unbalanced a motor 48 will be energized for rotation in one direction or the other by amplifier I2 to shift contact 34 along the slidewire 28 and collector bar 33 to a position in which the network is again balanced, and to simultaneously shift the recording element in a direction at right angles to the direction in which it was moved by motor 21.

In the normal operation of the instruments the circuit connections are as shown in Figure 16. From time to time, as the batteries I3 diminish in strength the networks must be recalibrated or standardized by adjusting the resistances I8 and 29. When this is done the potentiometer circuits are disconnected from the input terminals I1 and I8, and II and 32 respectively, and have a standard cell 50 connected across a portion thereof. The same amplifier is used for both potentiometer networks during the standardizing operation.

To standardize the left network, the movable contacts of switch 20 are moved to the left by a bar that connects them. When this is done the converter I20 and standard cell 50 are connected in that circuit between points 49 and 26 by a connection including a wire extending from point 45 to stationary contact 5|, movable contact 52. cell 50, junction 42, and wire 43 to the transformer of converter I2a. From the converter the connection extends through wire 44, movable contact 45, and a stationary contact 53 to the junction point 26. At the same time this is done a resistance 54 is shunted across the converter I211. The circuit for this is from Junction 42, wire 4|, movable contact 38, and stationary contact 55 to resistance 54 and junction 26. The same operation that moves the contacts of switch 20 to the left is used to close a clutch It. so that as motor 48 is rotated due to unbalance of the left potentiometer network the standardizing resistance I6 will be adjusted by it in a direction to recalibrate the network.

In standardizing the right network, the input thereto is disconnected and standard cell 50 and converter I2a are connected across points 41 and 51 by shifting the movable contacts of switch 31 to the right. The circuit for this operation is from point 51 to movable contact 58, of switch 31, stationary contact 69, cell 50, junction 42 and wire 43 to the converter. From the converter the circuit includes wire 44, movable contact I! and stationary contact 48 to point 41. At the same time a resistance BI is shunted across the converter by a circuit extending from point 41 through the resistance 8|, stationary contact 82, movable contact 36 of switch 31, stationary contact 38 and movable contact I! of switch 20 and wire 4| to junction 42. The operation of moving the contacts of switch 31 to the right is also used to close a clutch 63 so that rotation of motor 48, due to network unbalance, may be used to adjust the resistance 29 and recalibratc the network.

As the networks rebalance themselves and cause the motors 21 and 48 to rotate, these motors through mechanism to be described later, move a recording element across a chart. The chart in this case is numbered 54 and is shown as being in strip chart form and upon which are printed a plurality of individual charts made up of rectilinear coordinates The chart supply roll 65, as best shown in Fieure 4 is mounted on one side of the chassis 4 while the takemp roll is mounted at 66 on the other side of the chassis. On its way from the supply roll to the to ke-up roll the chart passes a guide roll 61 which euides it across the front of a platen 6B in a guide roll 59 and a second guide roll H. runs the chart 1; moved from one side of the chassis to the other across the front or a writinr platen which serve-i to back up the chart while a record is beiiu: made upon it. The various resistances and condrmi-u. necessary for the potentiometer networks and the standard cell Eli are mounted on suitable supports provided on the bark oi the church 4 u i shown in F'iuule 3. For the sake oi ehnrnew. no wiring is shown in thai figure The supply roll 65 is monuled upon a role which is o designed that ll mlnihi tendency to rewind the chart upon this loll i. at all times present, which tendency can lu' i'iiiiiiillli by the slipping of a friction clutch when the chart is moved. Thus the chart is at all timesheld under tension so that the portion thereof in front of the platen will alway be taut. As: shown in Figure 8. the supply roll support con ,ists of a shaft 12 upon the upper end of which is rohunuir mounted an elongated collar I3 and upon the lower portion of which is mounted a second collar M. These collars serve to support a drum that has rigidly fastened to its lower end a flange 16. The chart supply roll is mounted on the drum l5 and is kept from rotating with respect thereto by means of a spring 11 whose upper end is adapted to he received in the usual notch formed in the core of the chart roll. This spring is attached to the collar 13 by means of a screw 18 and its upper end extends through a notch 19 formed in the surface of the drum 15. The upper end of the shaft 12 has non-rotatably mounted on it a collar Ill that is provided with an enlareed upper portion on th top surface of which is fastened a member 82 having fiat sides. Slideably mounted on the col lar ii is a disc 83 which is pressed upwardly into engagement with the lower surface of the enlarged upper portion of the collar by means of a spring 84. Shaft 12 also has rotatable upon it one member 85 of a jaw clutch that is attached by a pin 85 to the collar 14. The member 85 has a jaw 81 projecting downwardly from it which is adapted to engage a jaw 88 projectin upwardly from a second clutch member 88 that is also freely rotatable upon the shaft 12. These clutch members are normally maintained in the relation shown, in which the jaws 81 and 89 do not engage each other, by means of a torsion spring 9| that has one end projecting into the clutch member I! and the other end projecting into the clutch member II. Engaging the lower surface of the member 88 is a disc 92 of friction material that is pressed upwardly into engagement with The member 88 by means of a disc 93 that is siidably iii received on the lower end of the shaft 12. The shaft at this point is provided with flats on its surface with which the disc 88 cooperates so that it will not rotate relative thereto. Clutch member 88, disc 92 and disc 93 are forced into enagement with each other by means of spring 94, whose tension can be adjusted by a nut 95 that is threaded upon the shaft 12.

After the supply roll 86 has been placed on drum II with spring 11 in a notch in the roll tore, the assembly is placed in position in the chassis (Figs. 3 and 4) with part 82 received in a slot 91 formed in a bracket 98 attached to the top of the chassis. The lower end of shaft 12 is received by an opening in a bracket 98 attached to the lower end of the chassis. The chart roll is maintained in the proper vertical position by a screw 99 that is threaded into the bottom oibracket 98 to limit the downward movement of shaft 12. Washer 83 bearing against the lower surface of bracket 98 under the force of spring 84 assists gravity in holding the assembly in position In operation, as the chart is moved across the surface of the platen the chart roll will cause the tirum F5 to rotate with it. As the drum rotates it will first move clutch member until the jaw Bl thereof engages the jaw 89 of clutch member 88. Thereafter. the clutch member 88 will also be moved against the friction provided by the encasement between it lower face and the friction disc 92. When the chart has stopped bein moved, spring 9| will tend to unwind itself to separate jaws 81 and 89 and thereby place the chart under tension. From the above it will be seen that when the chart is initiall moved, the sprinp, BI is placed under tension and thereafter the chart drum 15 will be rotated against the friction of the disc 92. When the chart is no longer moved, clutch member 88 will remain \II it; new position and the spring 9| will place chart under tension.

The take-up roll 66 (Fig. l) is placed on a drum I0! and is held in position thereon by a flange ill? on the lower end of the drum against which the roll rests. Drum I! is fastened to a shaft Hi3 passing through it, which shaft has a collar I04 rotatably mounted on its upper end. In mounting the assembly in the instrument the collar is placed in a suitable holder Hi5 attached to the chassis with the lower end of shaft )3 in a snitable bearing in the frame. Collar Ill is held in the frame Hi5 by means of a collar I06 that tears against the bottom of the frame under the force of a spring I01. If desired the take-up roll can be rotated manually by means of a knob Hill, but the take-up roll is ordinarily driven by frictional engagement between its surface and the surface of a friction driving roller I09.

The friction drive roll I09 (Figs. 4 to '7 is rotatably supported in an upper arm I l I and a low er arm H2, which arms are pivotally mounted on a vertically extending shaft H3. In order that the arms may have a good bearing on shaft H3 each of them has a sleeve attached to it through which the shaft extends. One of these sleeves is shown at i ll in Figure 6 as being attached to arm Iii. It is noted that guide roller 68 is aim mounted to rotate around shaft I I3 and is then fore provided with bearings that surround the shaft, one of which is shown in Figure 6 below sleeve Ill.

Normally the friction roll (09 is spring pressed into engagement with the surface of the take-up roll 66 so that upon rotation of the friction roll I09 the take-up roll will be rotated also. To this end a spring H is wrapped around the sleeve H4 and has one end attached thereto, while the other end bears on a portion of the chassis 4. This spring serves to force the arms III and H2 on a clockwise direction in Figure 4.

A special construction is used on the upper and lower ends of roll I09 to make sure that there will be sufficient friction between that roll and the take-up roll 06 to drive the latter. Since the upper and lower ends of the friction driving roll are made in exactly the same manner, only the upper end thereof is shown in section in Fi ure 6. It will be seen that this driving roll is mounted upon sleeves IIB that are in turn attached to a shaft II1 by means of a set screw 8. The shaft H1 is suitably journaled for rotation in arms II and H2. The upper end of the sleeve H6 is reduced in diameter as shown, and has placed upon it a number of friction discs II!) that may be made of some material such as composition cork or fibre. These discs are tightiv held in engagement with the sleeve IIG by means of a nut I2I that is threaded upon the upper end of the sleeve. The discs H9 are slightly larger in diameter than the roller I09 so that as the roller is rotated, these discs will bear upon the surface of the take-up roll to drive the fflml'f. Due to their friction characteristics, there will be no slippage between the take-up roll and the friction driving roll.

Rotation is imparted to the driving roll I09 by means of a gear I22 fastened to the upper end of the shaft II1. This gear meshes with a pinion I23 mounted on the arm .III which pinion in turn is driven by a gear I24. 6. this gear has a tubular extension that is .ionrnaled in the chassis 4 and which is attached to a bevel pinion 25. The upper end of shaft H3 is received by the bevel pinion which acts as a bearing therefor. The pinion I25 meshes with a second beveled pinion I26 that is attached to a shaft I21 which is journaled in bearings I28. In the operation of the device. a knob I29 on the front end of shaft I21 is rotated to rotate the pinion I26. and the various gears forming the gear train between that pinion and gear I22. so that the drum I09 can be rotated to drive the take-up roll.

Normally the knob I29 is rotated in a direction so that the chart will be wound up on the roll 65. I

In order to prevent retrograde movement of the roll I03, the shaft I21 has mounted on it what is, in effect, a one-way brake. To this end the rear hearing I28 for the shaft I21 has in it a hardened steel bushing I3I that receives the s aft. Mounted on the outer end of the shaft is a cup shaped member I32 of such a diameter that an annular space is left between this member and bushing I3I. Within this space is a coil spring I33 that loosely encircles the bushing and which has one end attached to the cup shaped member. This spring is wound in such a direction that upon rotation of the shaft I21 in a direction to feed the chart to roller 66. the spring will tend to expand into engagement with the inner surface of the cup member. Upon rotation of the shaft I21 in a reverse direction, however. the spring I33 will grab the outer surface of the bushing I3I to prevent or retard rotation of the shaft I21 in that direction. From the above it will be seen that since the friction roller I09 cannot turn in a reverse direction, the sprin': III in the supply roll can pull the chart tight without having a tendency to unwind it from t'ze take-up roll.

As shown in Figure At times it may be desirable to tear off each of the sections of the chart after it has had 9. record drawn upon it, rather than saving all of these sections in a roll. If this is the case, the chart will be directed from the guide roll 1|, as seen in Figure 4. between the drum upon which the take-up roll is normally mounted and the friction driving drum I09, around in front of that driving roll and behind a cutter member I34. When this type of chart drive is used. the chart is pinched between the take-up roll and drive roll I09 to be fed forwardly below the cutting edge. When the chart has been advanced sufliciently. it may be pulled downwardly against the cutting edge to be torn off in sections. An indicator I on the chassis (Fig. 1) cooperates with the chart to show when it is properly positioned.

In order to simplify the attaching of the chart to the take-up roll and the threading of the chart around guide rollers 69 and 1|. a means is provided to hold the friction drive roll I00 out of engagement with the take-up roll 66. For this purpose a hook I40 (Figs. 1 and 5) is fastened to the lower portion of the chassis back of scale 223. When a new chart is to be placed in the instrument the friction drive roll I0!) is moved clockwise in Figure 5 against the force of spring H5 until the hook I40 is engaged hehind the bent edge of the cutter bar I34. The friction drive roll will then be held in inactive position until it is released by removing the hook from the cutter bar.

The pen which is used to make a record on the chart is mounted on a vertically movable carriage that is in turn mounted on a horizontally movable frame. Because of this type of mounting the pen can be moved in any direction across the chart to record the varying values of the two conditions that are being measured. As shown in Figures 1, 10 and 11. the pen I35 comprises an angle member I35 that is made of thin sheet metal which is bent as shown in Figure 10. The ends of this angle member are attached to a frame I31 whose rear ends extend to the right in Figure 11 and terminate at an angle as shown at I38. A combination reinforcing and pivot pin I30 joins the upper and lower portions of the frame. The writing point for the pen is formed by the end of a piece of capillary tubing III which extends rearwardly into engagement with the chart at the angle formed in the member I36. From its writing tip, the capillary tube extends down through the lower arm of the angle member and into a transparent ink receivin container I42. This container or cup is suitably fastened into a holder I43 which is attached to the lower end of the frame I31. The pen frame is also provided with a forwardly extending part I44, the purpose of which will be pointed out later.

A pen carriage is provided upon which the pen is mounted and has its frame member formed of a U-shaped part I45. Attached to the end of one of the legs of the U is a pair of brackets I45 which are mounted one above the other at a distance apart. so that they come just inside the ends of the frame member I31 of the pen. Also attached to this end of the U member I45 is a spring I41 which extends across in front of the brackets I40. The pen is mounted on the pen carriage. as best shown in Figure 11. by moving the pen into engagement with the spring I41, and then to the right along this spring until the pivot pin I39 moves under and into engagemeat with a notch formed in the brackets I44.

The pen is then held in position with the pivot pin being pressed into engagement with the brackets I46 by the spring I41 as is best shown in Figure 11.

In order to guide the pen carriage in its vertical movement a block I 48 is attached to the cross member of the U I45. This block has a pair of rollers I48 on its upper end and a pair of rollers II on its lower end which rollers, along with a third roller I 52 located in a vertical position midway between rollers I48 and I51, engage a vertically extending rod Ill.

The carriage is also provided with a pair of front rollers I54 and I55, the latter of which is supported on the pen carriage by means of a supporting member I58 that is attached to the U-shaped member by suitable screws. It is noted that these screws also hold a spring I51 which is adapted to bear against the right face of the part I44 on the pen to force the pen in a clockwise direction around the pivot pin I88 into engagement with the chart. Rollers I54 and I55 engage one of the flanges of a channel member I58 which extends in a vertical direction and is parallel to the rod I53. It will be seen that the cooperation of the various rollers with the rod and with the channel hold the pen carriage in a predetermined position relative to the chart so that the pen will at all times engage the chart as the pen carriage is raised and lowered.

Rod I53 and channel I58 form part of a movable frame upon which the pen carriage is mounted; which frame is adapted to be moved transversely of the instrument from left to right in Figure l. The frame. as seen in Figure 9, consists of an upper plate member I59 and a lower casting Iii to which the rod and channel member are fastened. The plate and casting also have extending between them two other rods, I62 and I63. The frame is supported in a fixed vertical position by rollers I55 and I88 which bear against the top and bottom of a horizontally extending rod I81. There is also provided a plurality of rollers I84 which bear against the sides of rod I81 to definitely locate the path through which the frame will move. The upper end of the frame is restrained to move through a given path by means of rollers I68 and I58 which bear against the front and back of a rod I12 that extends transversely of the frame parallel to the rod I61. In order to keep the frame aligned vertically and to make sure that the upper end of the frame is exactly above the lower end of the frame as it is moved across the instrument, the rod I5! is rotatably mounted in the frame and is provided on its ends with pinions I13 and I14 which mesh respectively with racks I15 and I18 (Figure 9) that are attached to the chassis 4 above and below the writing platen. Therefore, as the frame is moved across the front of the instrument, the engagement between the racks and pinions will insure a continued vertical position of the same.

The frame carrying the pen carriage and pen is moved horizontally across the front of instrument by means of the motor 21 in response to unbalance of the left hand potentiometer network in Figure 16. To this end. the motor 21 is attached to the lower part of the chassis 4, on the back thereof, as shown in Figures 3 and 5. As the motor rotates, it drives a pulley I11 through suitable gearing, including a gear I18 that is formed on the pulley. Rotation of the pulley is which has its ends wrapped around and attached to the pulle I11. The central part of the cable extends from the lower surface of the pulley around guide pulleys I8I and I82, the latter of which is biased in a clockwise direction in Figure 5 by a spring I88 (Fig. 3) in order to keep the cable under tension. Movement of the cable as the pulley I11 rotates is imparted to the frame due to the fact that the cable is attached to the casting I6I of the frame by means of a block I83 which grips the cable between itself and the casting. A screw I84 is provided for this purpose.

As the pulley I11 is rotated by the motor 21, it is shifted axially so that the cable will be fed on and off of the pulley in a helix. This prevents the convolutions of cable from piling up on one another and binding. In order that the pulley may be shifted axiall as it rotates, it is provided. as shown in Figure 13, with internal screw threads I85 that engage similar threads on a shaft I85 around which the pulley rotates. This shaft is held against rotation in its mounting in the instrument. The shaft is mounted by having one end placed through an opening in the chassis 4 and its other end placed in an opening in a bracket I92 that is attached to the chassis, as best shown in Figure 5. The shaft is provided with an enlarged portion I81 On one end which serves to helpsupport the pulley and hold it rigid as it rotates. Extending through the pulley I11 and projecting from both ends thereof is a stop pin I88 that serves to positively limit the numher of revolutions which may be imparted to the pulley as it rotates. If the pulley is rotating in a direction to move the frame to the right in Figure 5, the screw threads are such that it will be moved downwardly since the cable will be fed on from the right and of! from the left. When the frame has reached the end of its travel the lower end of pin I88 will engage stop I89. If the frame is moving in the other direction or to the left in Figure 5, the pulley I11 will be moved upwardly until the upper end of the pin I88 engages against the stop I90. Since it is necessary that the movement of the frame be limited to exactly the extent of the calibrated portion of the chart, one of the. stops, and in this case the stop I88, is made adiustable by means of a screw Iiil that extends through the bracket I92. In adjusting the above described mechanism the pulley I11 Is rotated until the lower end of pin I88 engages stop I89. The frame is then attached to the cable with the frame in a position so that the recording tip of the pen is on one edge of the calibrated portion of the chart. The motor 21 is then energized for rotation to move the frame in the opposite direction until the recording tip of the pen engages the other end of the calibrated portion of the chart. This is approximately three and one half rotations of the drum I11 and its diameter is made so that this is the case. In order to definite- 1y limit the travel of the frame at this point the screw I9I is adjusted to move stop I88 into engagement with the pin III.

From an inspection of Figure 13, it will be seen that the pulley I11 is also provided with openings I93 and I84. These openings are intended to receive the ends of the cable so that the cable ends may be clamped in the pulley by screws that are threaded through suitable openings in the pulley that are transverse to them. The cable ends are initially pulled tight enough so that spring I88 will be under tension thereby keeptransferred to the frame by means of a. cable I18 ing the cable taut.

As has been pointed out above, the movable frame is moved transversely of the instrument when the potentiometer network is unbalanced. This movement continues until the network is rebalanced, and the balance point is determined by the proper position of contact 2| along slidewire l and collector bar l9. To this end the contact If is resiliently mounted on the upper plate I59 of the frame as shown in Figure 9. The slidewire l5 and collector bar is are mountrd above the contact in an insulating block I95 that is in turn fastened to a support I96. This support is pivoted on a shaft i51 extending transversely of the chassis in such a fashion that the slide-wire and collector bar are directly above the contact. Since it is necessary that the slide-wire be given some particular position above the contacts. stop nuts I28 are threaded on the shaft I91 to positively position the left end of the support I96 as is shown in Figure 4. The frame I96 is definitely located above the contact b engagement between projections I99 extendlni'. from each end thereof and the upper surface of the chassis 4. and is kept in this position by a screw 2lll which engages the rleht extension I59. In order to clean the slide-wire from time to time the frame may be swung around shaft I91 as a pivot after screw has been removed. This positions the slide-wire support so that the slidewire is facing upward in an accessible position.

The pen carriage is moved verticaly on the shiftable frame by the motor 40 in response to unbalance of the right hand potentiometer network in Figure 16. For this purpose. the motor is mounted on the lower portion of the chassis .1 and over to one side beyond the travel of th frame. As best shown in Figure 14. the motor drives a shaft 202 which is received in a housinc 203. The outer end of the shaft has a s iral gear 20! on it which meshes with a similar s iral gear fastened to a splined shaft 205. the latter shaft extending transversely across the lower portion of the chassis of the instrument and journal d for rotation therein. It is noted that the shaft 202 is provided with suitable thrust bcarin'zs 2M and 201 and that the shaft 205 is provided with similar bearings which are not numbered. As the splined shaft 205 rotates. it rotat:s a nul ev 208. as shown in Figures 5 and 9. which pulley is slidably received on the shaft 205 and is moved along the shaft as the frame moves b portions of the casting IBI which engage its sides. The pen carriage is raised and lowered by a cable 209 which has its ends fastened to pullzy 208. The center portion of the cable passes over a pulley 2l0 as shown in Figure 9. which pulley is mounted in the upper portion of the movable frame bv means of a pair of ang e brackets 2 that are located on top of the plate I59 by means of pins 2". Pulley 2 I0 is normallv biased in an upwardly direction in order to maintain the cable 209 under tension by a pair of springs 213 which surround the pins M2 and are located between the u er surface of plate I59 and the lower surfac of the angle brackets 2. As the cable is driven it moves the pen carriage bv a clamp 2 II that hods the cable tightly against the carriage and a screw 2|! that serves to hold the clamp in place.

Unbalance of the potentiometer network causes the motor 48 to start rotating to raise or lower the pen carriage. When the potentiometer network has been rebalanced the motor will stop rototing. To this end the contact is attached to the side of the pen carriage and extends into engagement with the slide-wire I3 and collector bar 28 that are mounted on a vertically positioned insulating block 2l8. This block is fastened to a support 211 that is pivoted to move around the shaft I63. Normally the support is held in the position shown in Figure 11 by means of a latch including a finger 2"! that is slideably mounted on the support and which finger engages the turned up edge of a bracket 2|9 that is attached to the channel I59. The resiliency of the contact 34 hearing against the slide-wire tends to move the support 2" in a counter-clockwise direction in Figure 11 until the latch 218 engages the bracket 2l8. In this manner the slide-wire is definitely positioned relative to the contact. By moving the latch 2I8 upwardly in Figure 11. its lower end will be brought out of engagement with the bracket 2 I 3, and the entire slide-wire assembly may be moved to a position in which it is accessible for cleaning.

It is noted that the holder I56 for roller I serves as a pointer to indicate the position of the carriage alone: a scale 22i that is attached to the front portion of the channel member I58 and the bracket 2l9. It is also noted that the frame has on it a pointer 222 which cooperates with a scale 223 that extends across the lower portion of the instrument to show the position of the frame with respect to the chart. The scale 223 is attached to a frame member 224 that is pivoted on the lower part of the chassis at 225. Thus the frame and the scale carried by it may be moved in a clockwise direction in Figure 9 to give access to the mechanism on the lower part of the chassis.

A stop is provided to limit the rotation of motor 8i! so that. the pen carriage may not be i mre'l above or below the calibration marks on the chart. To this end. as seen in Fizurc l4. :1 drive member 226 is formed as a projection on the pinion 221 that is placed on the motor shaft. Rotatablc on the shaft 202 and reading from left to right are a series of parts that are driven by the member 226 and which serve to act as a stop to limit rotation of the shaft 202. These memhers are. part 228 having a lug 22!! extending upwardly therefrom. bent member 23L one end of which extends to the right and one end of which extends to the left. There is also a second part 232 having :1 lug 233. a second bent member 234. a third part 235 having a lug 236 and a third bent member 231. It will be seen that as the shaft 202 is rotated. the drive member 226 will move part 228 until its lug 229 engages one bent over portion of member 23!. The latter member will then be driven by part 228 and its bent over end extend ng to the right wil engage the lug 233 on part 232 to drive the latter. In this manner, one of these members after the other will be picked up rntil such time as the arm extending from the ri ht of member 231 engages the lower end of a screw 238 that extends into the housing 203. This positively stops the shaft 202. Upon a reverse rotation of the motor 40. the various parts will be picked up in sequence and rotated in the opposite direction until the member 231 engages the other side of screw 238 to positivelv stop the rotation of the shaft in that direction. The screw 23! is formed with a conical end so that bv moving it further into or out of the housing 203 the shaft 202 will be permitted to rotate more or less. This is an adjustment which will permit a definite limiting of the end of the movement of the pen carriage with the writing tip of the pen at the edge of the chart ca'ibration marks.

When moving the chart from beneath the pen after a record has been made, it is necessary to lift the pen up away from the chart so that it will not make an undesirable line thereon. This may be done by maving a. bar member 235 in Figure 11 clockwise around shaft 062 into engagement with the rear ends I35 of the pen frame. Such engagement will pivot the pen around shaft I39 and raise its writing tip out of engagement with the chart. The member 255 consists of a bar which has its ends bent over as shown in Figure 9 and perforated so that they may be received by the shaft I52. This bar is located vertically along the shaft by means of a collar 24! that surrounds the lower part of the shaft and extends between the bar 229 and the pinion I14. The bar is rotated around shaft I52 by means of an eccentric 242 which is received between the arms of a yoke 242 that is attached to the upper end of the bar 235. Rotation is imparted to the eccentric by a shaft 244 upon which it is slidably received, the shaft extending transversely of the chassis. It will be seen that the shaft has a flat on it so that as it is rotated, the eccentric will be rotated. The frame is provided with a pair of brackets 245 that are attached to the lower surface of plate 155, which brackets engage the ends "of the eccentric to move it along shaft 244 as the frame moves.

Shaft 244 is held in its rotated .positions by means of a mechanism which is shown in detail in Figure 12. and which is mounted on the upper right hand portion of the chassis. With refermew Figure 12, it will be seen that the shaft 244 has a pinion 246 on its end, which pinion :z.

engages a rack that is formed on the upper surface of a sleeve 241 received in a suitable bracket on the end of the chassis. Extending through and supporting the sleeve is a shaft 248 which shaft is journaled in the bracket. The sleeve 241 and its rack are normally held in the position on the shaft 245 that is shown in Figure 12, by means of a spring 249 which surrounds the shaft and which bears with one end against an enlargement 25i on the sleeve and with its other end against a head 252 on the shaft. The assembly consisting of the shaft and the sleeve may be moved to the right from their normal position shown against the tension of a spring 253 that bears with one end against the bracket and with its other end against a push button 254. The left limit to which the shaft canbe moved is determined by a stop 255 that engages the head 252 on the shaft. A catch to hold the sleeve in its right position is provided by a lever 255, which is pivoted at 251 and which is biased in a counter-clockwise direction in Figure 12 by means of a spring 258 to a position limited by engagement between the opening 259 formed in the lever and a pin 26i projecting from the chassis 4. Lever 255 has formed on its upper surface a projection 252 and has pivoted at 254 on its right end a pawl 252., This pawl is biased in a clockwise direction by a spring 251 to bring a pin 255 on it into engagement with a pm 255 on the lever.

In the operation of this mechanism. the button 254 is pushed to the right until head 251 on the sleeve engages behind the projection 242 on lever 255. In this position shaft 244 has been rotated and, through eccentric 242 and yoke 243. the bar 233 has been moved so that it is against the end I38 of the pen frame. The writing point of the pen is therefore moved out of engagement with the chart. When the button 224 14 is again pushed, the head 252 will bear against the upper end of .pawl 255, camming the lever 262 in a clockwise direction in Figure 12 far enough to permit the projection 252 to move below the head 251. When this happens, spring 249 will move the sleeve and its rack 241 to the left rotating shaft 244 so that the bar 233 will be moved away from the ends I38 on the pen, permitting the pen point to move toward the chart under the force of spring I51. It will be seen that if the button 254 is pushed all the way, head 252 will move the lever 255 clockwise while 25i moves to the right of projection 252. On the return movement of shaft 245. the left face of the head 252 will engage the right face of pawl 263 and rotate the latter against its spring tension around its pivot 254. Since the lever 256 is not moved, shaft 245 returns to the left and head 25I will stay behind the projection 252. Thus it will be seen that a movement of the button 254 all the way to the right will operate the mechanism to lock head 25i behind the projection 252 and raise the pen from the paper while movement of the button 254. only a portion of the way to the right, will effect the release of the sleeve 241 so that the pen will be moved against the chart.

As was pointed out above, the instrument must be standardized from'time to time to compensate for decrease in the voltage of the batteries i3. This is done by connecting the standard cell 55 into the circuit and by adlusting the rheostats l5 and 29 to recalibrate the potentiometer network. "I'he rheostats l6 and 28 are similar in construction and are mounted on the back of the chassis near the bottom thereof This construction is shown in detail in Figure 15 wherein it will be seen that each of the resistances is of the so-called vernier type and comprises a fine winding 265 and a coarse winding 259 that are mounted on discs which are rotatable around a shaft 21I. These windings are adjusted with respect to contacts 215 by means of a gear 212 for resistance It and a gear 213 for resistance 28. The gear 212 is .provided with a rod 214 that projects therefrom through a hole in the disc for winding 255 and through a slot formed in the disc for winding 259. In this fashion as the gear 212 is rotated. the winding 26! will be moved immediately but the winding 259 will not be moved until after the rod 214 has been moved through the length of the slot formed in its disc. Thus upon the adjustment of the rheostat the coarse winding will not be moved until the adjustment provided by the fine winding has been used up. The gear 213 is provided with a pin 215 that cooperates with the discs upon which the resistances of the rheostat 29 are wound.

The gears 212 and 212 are rotated by means of ears 215 and 211. respectively, which are rotatable around a shaft 215 and wh ch are main-- tained in their position reative to the gears 212 and 213 by holding members 219 and 251 resp ctively. These members are attached to the framework and engage in grooves formed in h m of the gears. Shaft 215 is rotated bv the motor 42 through gearing which extends between the pinion 221 of the motor shaft and a gear 25! which is mounted on the shaft 215. Rotation of the shaft 215 is imparted to the gears 215 and 211 by means of the clutches 55 and 53 that have been mentioned above. These clutches consist of discs that are keyed to and slideable on the shaft 215 and which are resiliently pressed toward the outer face of the gears 210 and 211, re-

spectively. by springs 203 and 284. The opposite ends of these springs are held in position on the shaft by shiftable collars. Shaft 210 is moved axially to the left to bring clutch disc 58 into engagement with the face of gear 210 by means of a. shaft 285 that is journaled in a suitable frame 206 attached to the chassis. This shaft 205 is normally held in its position shown by means of a. spring 281 that surrounds the shaft 285 and is received in a recess in the frame 288. This spring bears against a button 280 on the outer end of the shaft 285. Connection is made between the shafts 205 and 218 by means of a collar 20! that is attached to the end of the 'shaft 218 and which receives the end of shaft 285. As best shownin Figure 15. the shaft 288 is formed with a groove in its end, which groove receives a set screw 20| extending through the collar 208. By means of this connection, axial movement may be imparted to the shaft 210 but that shaft can rotate without rotating shaft 285. Shaft 218 is moved to the right to bring clutch disc 83 into engagement with the adjoining face of gear 211 by means of a shaft 292 that is also iournaled in the frame 285. The shaft 292 is held in the position shown by means of a spring 203 that engages with a button 294 formed on the end of the shaft. It will be seen from the drawing that shaft 282 is formed on its upper side with a. rack that meshes with a pinion 295 that also meshes with a rack formed on the lower side of shaft 205. Thus. when the button 294 is pushed to the left. pinion 295 is rotated clockwise and shafts 285 and 218 are moved to the ri ht to close clutch 63.

In order to properly standardize the instrument. it is necessary to simultaneously shift the switch 20 when clutch 56 is closed and shift the switch 31 when clutch 63 is closed. The left end of shaft 252 is used for this purpose. Referring to Figure of the drawing, it will be seen that this shaft is formed with a cam surface 288 that will move the switch operating button 298 to the left when shaft 202 is moved upwardly in Figure 5, or to the right in Figure 15. Shaft 282 is also formed with a cam surface 291 that will movthe actuating button 299 for switch 31 to the right when shaft 289 is moved downwardly in Figure 5 or to the left in Figure 15. Thus it will be seen that when the buttons are pushed to close clutch I56, switch 20 will be thrown, and when clutch 63 is closed switch 81 will be thrown. Any unbalance in the potentiometer circuits due to diminishing battery voltage will be compensated for by the motor 40 as it rotates and adjusts the resistances It or 29 respectively.

At times it may be desirable to have several records on one chart. for example, to plot several pressures against a single temperature. If so, some means of identifying the various records is required. This can be accomplished by giving a distinctive log or movement to the pen as it moves across the chart in making each record. Figure 17 shows the kind of records that may be made following this method. For example, record A is a single straight line that does not have any interruptions in it. Record B is a line that has single humps or jogs made in it as the pen crosses the calibration marks for 20, 40 and 60. Record C has similar humps in it when the pen crosses the records marks for 10, 30 and 50. Record D has double humps in it as the pen crosses calibration marks 20, 40 and 60. Record E has double humps in it as the pen crosses one of the calibration marks 10, 30 and 50. Record F has a hump made in it each time the pen crosses one of the calibration marks 10 to 60 inclusive. This may be accomplished by paralleling one of the calibrating resistances 20f in the potentiometer network that controls the vertical movement of the pen with another resistance 302. The resistance 202 can be made adjustable, and in this way the height of the humps placed in the various records may be adjusted.

The instrument is manually connected to the six pressures by any suitable means and at the same time a switch shown in Figure 16 is adjusted. This switch has twelve contacts, a to l, inclusive. which contacts are connected by means of a brush 203 to a commutator shown generally at 304. This commutator. as is shown in Figures 3 and 5. is mounted on the lower rear portion of the chassis 4 of the instrument and is driven through gearing Si! by the motor 21 that moves the pen in a horizontal direction. The commutator consists of three rings 305, 306. and 201, the first two of which are engaged respectively by brushes 208 and 200 on one side and r all three of which are engaged by brushes 3". 2l2 and 3!! respectively at diametrically opposite points. These commutator rings are mounted on a. shaft 2 that is lournaled for rotation in the chassis I and is driven by the above mentioned gearing Iii. The brushes are insulated from each other and from the chassis by being mounted on an insulating block 3IG that is held in place above the commutator by a bracket M1.

Referring to Figure '16 of the drawing it will be seen that ring 201 of. the commutator is conducting around its entire surface. Ring 306 is conducting for only a. short length of its surface and ring 205 is formed with a similar short conducting surface that is displaced clrcumferentially by a small amount from the conducting surface on ring 200. The conducting portions of rings 205 and 300 are electrically connected to ring 301. The conducting portions Lof rings 305 and 308 are also placed with respect to the contacts engaging them and with the motor 21 that they will be engaged by contacts 300 and 309 as the pen passes calibration marks 10 and 30 and 50 across the chart, and will be engaged by contacts 0H and M2 as the pen passes calibration marks 20, 40 and 60 across the chart.

If record A is to be made, brush 303 will be shifted to engage contacts a and 9. Since these contacts are not connected to anything the resistance 20! will not be disturbed and a smooth line will be drawn. If record B is to be made. brush 808 will engage contacts 2; and h, the latter of which is connected to brush 3| 2. Therefore as the pen is moved and the commutator r0- tated resistance 802 will be placed in parallel with resistance "I when the pen is at 20, 40 and 60 across the chart so that a bump will be placed in the record at these points. If record E is to be made. brush 803 will engage contacts c and i that are connected respectively to brushes 308 and 208. Therefore. when the conducting portions and 800 pass under the brushes 308 and 309 as the pen crosses calibration marks 10, 30 and 50 on the chart resistance 802 will be placed in parallel with resistance "I to put bumps in the record as shown in Figure 17. A Records C, D and F are made in similar fashion. When rec- 0rd C is made brush 002 engages contacts I and I. When record D is to be made brush 20! engages contacts d and 1, and when record F is to be made brush 202 engages contacts e and k.

The general operation of the device should be 17 apparent from the above detailed description. The instrument is adapted to make a graph of two variable conditions, and in so doing uses two potentiometer networks, one of which is unbalanced as the vertical component of the graph changes and the other of which is unbalanced when the horizontal component of the graph changes. Thus, the pen can be moved across the chart in response to variations in th variables. The instrument is compact and the various parts are readily accessible for adjustment and repair.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of this invention now known to me, it would be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of this invention as set forth in the appended claims. and that in some cases certain features of this invention may sometimes be used to advantage without a corresponding use of other features.

Having now described this invention, what I claim as new and desire to secure by Letters Patent is:

'1. In a recording instrument, the combination of a recording element, an elongated frame upon which said element is mounted. means to mount said frame for movement through a path, said mounting means including spaced apart guide means and anti-friction means on said frame cooperatingwlth said guide means, .means attached to said frame adjacent one of said guide means to move said frame through a path, and cooperating means on said mounting. means and on said frame and extending across said spacedapart guide means from said end of said frame connected to said drive means to the other end of said frame, thereby. positively to drive said frame from both ends to maintain said frame in the same position relative to said guide means and the path through which it moves as it is moved.

2. In a recording instrument, a combination of a recording element, an elongated frame upon which said element is movably mounted, a supporting part, guide means on said part. spaced apart means on said frame cooperating with said guide means, means to move said frame relative to said supporting part in a path determined by said guide means and by said spaced apart means, said means to move acting on said frame adjacent one of said spaced apart means, and means extending between said frame and said supporting part from the end of said frame on which said means to move act to the other end of said frame, to maintain said frame in a given relation to said supporting part as said frame is moved.

3. In a recording instrument having a recording element, the combination of, a movable frame, means to support said recording element on said frame, means to mount said frame for movement through a predetermined path to a position dependent upon the value of a measurable condition. drive means to move said frame, a drive pulley rotated by said drive means, a cable attached to said pulley and fed on and oil the same as said pulley is rotated. means toattach said frame to said cable to be moved thereby, and means to shift said pulley axially as it rotates to lay said cable on said pulley in a helix.

4. In a recording instrument having a recording element, the combination of, a frame upon which said element is mounted, means including a cable attached to said frame to move said 18 frame through a path having given limits, a drive pulley around which said cable is wrapped, means to rotate said pulley, means to shift said pulley axially as it is rotated to lay said cable on said pulley in a helix, and means to positively limit the axial movement of said pulley.

5. In a recording instrument having a recording element, the combination of, a frame upon which said element is movably mounted, means to move said frame through a given path including a cable attached to said frame, a drive pulley to move said cable, means to rotate said pulley, means to shift said pulley axially as it is rotated, a first stop to limit the axial movement of said pulley in one direction when said frame has reached one end of its path, a second stop to limit the axial movement of said pulley in the opposite direction when said frame has reached the other limit of its path of travel, and means to adjust said second stop so that the end position of said frame may be accurately determined.

6. In a recording instrument having a recording element, the.combination of, a carriage upon which said element is mounted, a frame upon which said carriage is mounted, means to move said frame back and forth through a given path, means to move said carriage through a path on said frame at an angle to the path through which said frame moves including a drive pulley on said frame, a shaft extending parallel to the path through which said frame moves and upon which said pulley is slidably and non-rotatably mounted, whereby as the frame is moved through its path rotation of said shaftwill be imparted to said drive pulley, a second pulley mounted for rotation on said frame, a cable passing in a loop around said pulleys, said cable being wrapped around said drive pulley and means to attach said carriage to said cable whereby as said shaft is rotated said carriage and recording element will be moved along said frame.

'7. In a recording instrument having a recording element, the combination of a movable frame, means to guide said frame through a path, a carriage mounted for movement on said frame including guide means to direct said movement through a given path. means to move said carriage on said frame including a cable attached to said carriage, a pair of guide means to support said cable and to one of which said cable is attached. means to bias the other of said guide means away from the guide means to which said cable is attached in order to keep said cable taut, and means to drive the guide means to which said cable is attached at any position of said frame whereby said carriage may be moved in its path on said frame.

8. In a recording instrument having a recording element, the combination of, a frame mounted for limited movement, a carriage to which said element is attached, means to mount said carriage for movement through a path on said frame, means to move said carriage through said path at any position of said frame. and stop means to determine the limits of the path through which said carriage is moved including a rotatable member driven by said. means to move said carriage and having a projection thereon. and an adjustable member in the path of said projection to limit the rotation thereof.

B. In a recording instrument, the combination of a member to back up a chart upon which a record is to bemade, a frame movable in one direction along said member, a carriage mounted on said frame for movement in a direction at right angles to the direction of movement of said frame, a recordingelement mounted on said carriage to engage a chart on said member, means to bias normally said element into engaging position, means carried by said frame and engaging said element at any position of said carriage on said frame to lift said element out of engaging position, and means mounted on said member and extending parallel to the direction of movement of said frame to operate said means engaging said element.

10. In a recording instrument, the combination of a member to support a chart while a record is being made thereonya frame mounted for movement in one direction across said chart, a carriage mounted for movement on said frame in a direction at right angles to the direction of movement of the frame, a recording element adapted to engage a chart on so id mcmhci'. means to support said element on said carriage. means to press resiliently said element into engagement with the chart, and means to move said element out of engagement with the chart at any position of said carriage and said frame including a bar rotatably carried on said frame and movable into and out of engagement with said element, a rod on said member and extending parallel to the path of movement of said frame, means operated upon rotation of said rod to rotate said bar to move said element out of engagement with the chart or permit it to move into engagement therewith, and means mounted on said member to rotate said rod to various positions.

11. In a recording instrument, the combination of a member to support a chart upon which a record is to be made, a frame, means to mount said frame for movement on said member across the front of the chart, a carriage. means to mount said carriage for movement on said frame at right angles to the direction of movement of said frame, a pen, means to mount said pen on said carriage for movement around an axis so that the pen may be moved into and out of engagement with the chart, means to bias normally said pen into engagement with the chart, means mounted on said member operative to lift said pen from said chart, and connecting means mounted on said frame and operative to transfer movement of said lifting means to said pen at any position of said frame and said carriage.

12. In a recording instrument, the combination of a frame, means to move said frame to positions along a path corresponding to the value of a variable condition, a carriage, guide means on said frame upon which said carriage is mnnnted for movement, a recording element pivniml to said carriage, means on said carriage to him: normally said recording element to recording position. means on said frame engaging said recording element at any position of the latter to move said recording element out of recording position, a cable attached to said carriage. pulleys on said frame adjacent the ends of said guide means over which said cable passes in a loop, and means to rotate one of said pulleys to move said carriage on said frame at any position of said frame.

13. In a recording instrument, the combination of, a recording element, supporting means. a pair of guide means attached to said supporting means, a frame on which said recordinr element is mounted to move over a record sheet. means to mount said frame for movement alon said guide means, a rack member adjacent and parallel to each of said guide means and attached to said supporting means, a shaft journaled attached to said frame, a pinion on each end of said shaft so as to be rotatable with said shaft. each of said pinions meshing with one of said rack members whereby as said frame is moved engagement between said rack member and pinions will keep said frame in the same angular position relative to said supporting means, and means to move said frame along said guide means.

14. In a recording instrument, the combination including, a support, a frame adapted to carry a recording element in contact with a record-receiving chart so as to make the records thereon, cooperating guides and guide members interposed between said frame and said support to restrain said frame for movement except along a fixed path, a pair of rack members each adjacent and parallel to one of said guides and attached in said support, a shaft Journalled on said frame, a pair of pinions each pinned to a spaced portion of said shaft so as to rotate with said shaft and to mesh with one of said rack members, whereby engagement between said rack members and said pinions restrains said frame against canting or tilting movement relative to said support as said frame is moved, means to move said frame along said guides, and means to move said recording element along said frame.

15. In a recording instrument, the combination including, a movable carriage, a pen mounted on said carriage and adapted for making a record on a chart and comprising a box-like frame of sheet metal, a V-shaped angle member of thin sheet metal having the point of the V spaced away from the frame and over-lying the chart and having the ends of the arms of the V fixedly attached to the frame, a transparent inkreceiving container supported on said f rame, and a capillary tube extending from the point of the V along one of the arms of the V and into the container so as to conduct ink from the container to the marking space at the point of the V.

GEORGE W. BARNES. J a.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,316,658 White Sept. 23, 1919 1,452,122 McConnel Apr. 17, 1923 1,471,129 Holt Oct. '16, 1923 1,685,973 Alexander Oct. 2, 1928 1,784,522 Harrison Dec. 9, 1930 1,811,541 DuBois June 23, 1931 1,873,126 Hugershoii' Aug. 23, 1932 1,961,170 Robinson June 5, 1934 1,985,265 Smith Dec. 25, 1934 2,113,748 Ross Apr. 12, 1938 2,148,188 Chappell Feb. 21, 1939 2,224,182 Crooks Dec. 10, 1940 2,240,520 Schlumberger May 6, 1941 2,267,682 Fairchiid Dec. 23, 1941 2,275,248 Caldwell Mar. 3, 1942 2,277,427 Woodson Mar. 24. 1942 2,300,742 Harris n Nov. 3 1942 2,388,105 Wilson .H, Oct. no. 1945 2,392,916 Gruss Jan 15, i946 2,395,351 Sohn H--. 1.," Feb if), 1946 PORETQHJ PATENTS Number (mmirv Dnte 680.198 Germany Aug. 24. 1939 Certificate of Correction Patent No. 2,527,207 October 24, 1950 GEORGE W. BARNES, JR.

It is hereby certified that error appears in the rinted specification of the above numbered patent requiring correction as f0 lows:

Column 7, line 17, for the numeral 11 read 111; line 38, for 25 read 125; column 18, line 4, for maving read moving; column 20, line 3, for attached to said frame, a pinion on each read on said frame, a pinion attached to each;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofl'lce.

Signed and sealed this 22nd day of May, A. D. 1951.

THOMAS F. MURPHY,

Aasistant Commissioner of Patents. 

